US2742254A

US2742254A - Hydraulic fuse

Info

Publication number: US2742254A
Application number: US460635A
Authority: US
Inventors: Oscar H Banker; Harry A Hedland
Original assignee: New Products Corp
Current assignee: New Products Corp
Priority date: 1954-10-06
Filing date: 1954-10-06
Publication date: 1956-04-17
Anticipated expiration: 1973-04-17

Description

April 17, 1956 o. H. BANKER ETAL 2,742,254

HYDRAULIC FUSE Filed Oct. 6, 1954 I 3 Sheets-Sheet 1 FIG. 1 2 H 1m J; L W 1 sea, I r 34 Z9 L 2/2 :J 27

INVENTORS Oscar 1'2. Banker y HarryAJfea'Zand @12 9 April 17, 1956 HYDRAULIC FUSE 5 Sheets-Sheet 2 Filed Oct. 6, 1954 M Q W- mn film Mme 7 AK, 7' 5 l .W 54- m 3 9 F G H O. 6 1 c a e 2 L u @H 6 4 M4 5 m/ N n M 4 9 a fll/ny 5 w H N & 9 w 7 M 6 3 M w M 1 Z u I I. w ,2 I 45 8,71% my H 4 4 0 9 k k lew F 7 7 Hm m H 7 2 9 w w April 17, 1956 Filed Oct. 6, 1954 O. H. BANKER ETAL HYDRAULIC FUSE 5 Sheets-Sheet 5 La) 88 a9 Fl 34:

Oscar H Banker 2 Harry/17 1755116024 A94 United States Patent HYDRAULIC FUSE Oscar H. Banker and Harry A. Hedland, Evanston, Ill., assignors to New Products Corporation, Chicago, 11L, a corporation of Delaware Application October 6, 1954, Serial No. 460,635

17 Claims. (Cl. 251-46) This invention relates to safety shut-off devices for sealing a hydraulic line, when that line or some downstream component has been ruptured or has developed an inadvertent leak, said safety shut-off devices being commonly known as hydraulic fuses. This invention relates particularly to that type of hydraulic fuse known as the Quantity Measuring type. This type of hydraulic fuse is a device for automatically shutting off flow in a line after a predetermined measured quantity of fluid has passed through it. More particularly this invention relates to that type of quantity measuring fuse which will remain in a partially closed position should the flow be caused to cease after a partial cycle of operation. This type of fuse requires flow in the reverse direction to cause resetting after each cycle or partial cycle of operation.

In a hydraulic system which includes two or more reversible motors such as reciprocating pistonmotors, each of which is to be operated independently, a break in the hydraulic line to, or from, one of the motors, or a break in the motor, may inadvertently cause fluid to be lost which would reduce the quantity of fluid remaining in the main reservoir to the extent that the other motor or motors would become partially or completely inoperative. It is very desirable therefore under such circumstances to use a hydraulic fuse in the line to each motor which will automatically shut off a broken line so that as much fluid as is possible will be conserved in the main reservoir and the other motor or motors will not be affected by' the failure, but will continue to operate as required. a V

Where a hydraulic system is used to operate a plurality of essential motors such as the motors which operate the wing flaps, bomb bay doors, dive brakes, etc., of an aircraft, a loss of fluid. through an inadvertent leak in the system may become extremely serious. This is particularly true in the case of military aircraft, the hydraulic systems of which are subjected to the hazards of enemy gunfire.

Heretofore such hydraulic fuses as have been available have generally involved the use of a pair of orifices to divide flow into two paths in'such a manner that a relatively large stream of fluid was directed to the operating motor while a smaller but proportional stream was directed into a cylinder where the fluid was impinged against the face of a relatively free moving valve member contained therein. In the construction of this type of fuse it is required that the orifices divide the flow in such a manner that the downstream motor will receive the quantity of fluid required for normal operation prior to. the time the smaller orifice has passed the quantity of fluid required to fully operate the valve member and thereby close off all flow The problems encountered in manufacturing. a fuse of this type are many and great. Maintaining a proportional rate of flow through two orifices is virtually an impossible task under the many conditions of temperature, fluid density, fluid viscosity, pressure pulsations,

ice

etc. all of which are normally encountered conditions in an aircraft hydraulic system. Because of the relatively free moving valve member, it is diflicult to predict or control the action of the valve, particularly during low flow rate conditions when very low operating forces are present. Some fuses which have been manufactured have incorporated a free piston which was designed to be the exact weight of the volume of fluid which it, displaced and thereby be independent of acceleration forces. This can be shown to be an effective means of eliminating the effects of acceleration at one specific temperature, but as the temperature is changed the density and specific gravity of the fluid are also variedand the balancing effect of the piston weight is lost as the piston becomes either heavy or light in comparison to (the weight of its displaced volume of fluid. f v

"In the effective usage of hydraulicifuses in any hydraulic system it is required that sufficient fluid be pro-. vided in the main reservoir to permit the fuse to dump its maximum capacity under the worst ,possible anticipated conditions. In the case of the-type of fuse heretofore available this would be on the order of double the nominal rated capacity. In the case of a fuse that was rated at four hundred cubic inches the weight penalty incurred by adding the required extra capacity to the reservoir would be on the order of twelve pounds. This represents a very considerable amount of weight in the case of an airplane and could be reduced by the use of a fuse whose accuracy in metering were such that it would not pass such a great amount of fluid over its rated capacity. t v

In the hydraulic fuses heretofore available it was also true that if the hydraulic motor was operated through only a part of its cycle and then stopped for a period of time prior to completion of the cycle, there was no positive means of assuring that the fuse would pass the same total quantity of fluid as it would in a cycle wherein there was no intermediate pause orpauses.

An object of this invention is to. provide a hydraulic fuse which will more accurately'rneter the quantity of fluid passing through the fuse and thereby require less total quantity of fluid for complete protection of the system in which it is used than the fuses heretofore available.

Anotherobject of this invention is to provide a fuse the operation of which may be interrupted any number of times or for any length of time during a cycle and yet which will shut off the line after the predetermined quantity of fluid has passed through the fuse.

Another object of this invention is to provide a fuse which will be essentially insensitive to normally encountered variations in fluid viscosity, density and tem-.

perature and which will not be adversely affected by normally encountered forces of acceleration and vibration It is the further object of this invention to provide a;

These andother objects and features of this invention will become apparent from the following detailed description when taken together with the accompanying drawings, in which Fig. 1 is a schematic diagram of a typical hydraulic system showing the manner in which hydraulic fuses of this invention m y e used;

Fig. 2 is an enlarged exterior view of the hydraulic fuse of this invention;

2,742,254 Patented. Apr- 17, 1956 maintained byof this invention is to provide Fig. 3 is an end elevational view of the fuse of Fig. 2, taken in the direction of the arrows 3-3 of Fig. 2;

Fig. 4 is a cross sectional view taken longitudinally of the fuse substantially in the direction of the arrows 44 of Fig. 3, a portion of the interior of the fuse being cutaway to show the details of construction thereof;

Fig. 5 is a still further enlarged plan view of a subassembly of the fuse of 'Fig. 4, the subassembly including the greater portion of the rotating parts thereof;

Fig. 6 is a cross section through the subassembly of Fig. 5;

Fig. 7 is a cross section through the left-hand portion of the hydraulic fuse as viewed in Fig. 4, showing the fuse in an intermediate stage of its operation;

Fig. 8 is a fragmentary cross section of the fuse of Fig. 4 corresponding to that of Fig. 7, showing the final stage of operation thereof;

Fig. 9 is an end elevation in section taken through the vaned motor of the device looking in the direction of the arrows 9-9 of Fig. 4; and

Fig. 10 is an end elevation in section of the hydraulic fuse taken in the direction of the arrows 10-10 of Fig. 4.

A typical system in which the hydraulic fuses of this invention may be installed is shown in Fig. 1. In that figure suitable hydraulic fluid for operating a fluid motor under various conditions of temperature and pressure is stored in a reservoir from which it is drawn through a conduit 21 by a pump 22. From pump 22 the fluid is conducted through a conduit 23 to a pressure regulating valve 24, the excess fluid from valve 24 being conducted back to reservoir 20 through a return conduit 25.

Fluid under predetermined pressure is conducted from valve 24 through a conduit 28 to a motor control valve 26 provided with a control handle 27 by which the position of ,thevalve may be determined and changed by the operator. Fluid under pressure is also conducted through a branch 29 line extending from conduit 28 to an accumulator 30 Which provides momentary flow rates higher than pump output, or provides fluid under pressure at such time as the pump is not functioning.

The motor operated by the system is shown in outline at 31 and may be a reciprocating hydraulic motor, such as a piston operating in a cylinder. Such motor may be used to lower and raise the landing gear of an aircraft, or it may be used to operate a control surface on the aircraft, etc. In any event, it is contemplated that a predetermined quantity of fluid will be required to cause the motor to effect a movement of a rod 32 in one direction and that a predetermined quantity of fluid will be required to cause-a movement of the rod in the opposite direction, movement of the rod by fluid under pressure in one direction causing a forced evacuation of thefluid remaining in the cylinder as a result of the previous operation of the motor in the opposite direction.

Thus fluid under pressure may be conducted from control valve 26 to motor 31 through either conduit 33 or conduit 34, the motor being so arranged that when fluid under pressure is present in conduit 33 rod 32 will move upwardly, for example (as viewed in Fig. 1), and when fluid under pressure is present in conduit 34 rod 32 will be returned to its initial position. The flow of fluid in

conduits

33 and 34 is therefore reversed each time the movement of rod 32 and'its motor is reversed.

It is contemplated that the side of motor 31 not exposed to fluid under pressure will be vented through valve 26 and through a return conduit 35 which connects with return conduit 25 to conduct the vented fluid back to reservoir 20.

It may be apparent that should a break occur in either

conduit

33 or 34 while said conduits are connected through valve 26 to conduit 28 leading from valve 24 and pump 22, all of the fluid in reservoir 20 may be emptied through the break before the break is discovered and valve 26 is closed. Where the availability of fluid under pressure for the operation of other motors in a system supplied by the samereservoir is essential to the safety of persons using the system, or to the success of an operation of which the system is a part, the loss of the fluid would be extremely serious. It is the function of the hydraulic fuse to prevent such inadvertent loss of the fluid in a hydraulic system.

The hydraulic fuses of this invention are shown in outline in each of the

conduits

33 and 34 at 36 and 36a, respectively, it being understood that these fuses may be identical in construction and operation. The fuses are so constructed that when a predetermined volume of fluid slightly greater than the volume necessary to effect a complete operation of motor 31 passes through a fuse, it will automatically shut off the line and prevent further passage of fluid therethrough. It is contemplated that substantially all of the vulnerable portions of the

conduits

33 and 34 will be disposed between the fuse in such conduit and motor 31, since a break in the conduit between the fuse and valve 26, or, in fact, between the fuses and pump 22 will not be affected in any manner by the fuses and hence might still result in an inadvertent draining of the reservoir. The selection of the locations for the fuses in a system is a matter of design and forms no part of this invention.

The details of construction of fuse 36 are shown more clearly in Figs. 4 to 10, to which reference is now made. The fuse is contained within a cylindrical, transversely split housing preferably made of a part 37 and a part 38, the latter having a radially outwardly extending flange 39 which abuts the belled end 40 of part 37 and to which it is secured by screws 41. Flange 39 is spaced axially from the adjacent end 42 of part 38 and said end 42 is. piloted within the enlarged bore 43 of part 37 so as to be centered therein. A seal 44, preefrably of the 0 ring type, may be used to prevent leakage of fluid to the exterior of part 38 from between flange 39 and end 40 of l part 37.

, housing part 37 by a pin 47. Also secured to housing part 37 are

stationary side plates

48 and 49, side plate 48 being secured to ring 45 by a pin 56 and side plate 49 being secured to part 37 by the same pin 47 which holds the ring 45 against rotation relative to housing 37.

Side plates

48 and 49 are formed with central concentric openings 51 and 52 within which is rotatably supported a sleeve 53 extending through motor 46.

The rotor of the fluid motor is comprised of a cylinder 54 (Fig. 9) which has a central opening by which it is fitted closely over sleeve 53 and is prevented from rotating relative thereto by a pair of pins 55 disposed diametrically opposite one another in balanced relation. The interior surface of ring 45 is formed to fit closely theouter surface of rotor 54 at diametrically

opposed points

56 and 57 and between such points to form crescent-shaped

cavities

58 and 59 with the outer surface of said rotor 54. A plurality of radially disposed longitudinal slots 60 are formed in the outer surface of rotor 54 in each of which a vane 61 is radially movable. Each vane 61 is urged radially outwardly against the inner surface of ring 45 by individual springs 62 (Fig. 4) disposed in recesses 63 in the vanes and compressed between the vane and the bottom of the slot 60.

Side plate 49 is provided with a pair of diametrically disposed arcuate slots 64 and 65 which are in direct communication with inlet chamber 66 and threaded opening 67 of part 37, the threaded opening 67 being connected to the portion of the conduit leading from valve 26 and the source of fluid under pressure. .Side plate 48 is also provided'with diametrically opposed arcuate slots 68 and 69 which are in communication with a chamber 70 formed in housing part 38 and in communication with the threaded outlet 71 of the fuse which is connected to the fluid motor 31 to be operated by the system. It may be noted from Figs. 9 and 10 that-the disposition of openings 64 and 69 on the one hand and 65 and 68 on the other is such that fluid entering crescent-shaped chamber 58 through opening 64 will act against vanes 61 and tend to rotate the rotor 54 in a clockwise direction as viewed in Fig. 9. Similarly, fluid under pressure entering crescentshaped chamber 59 thr'ough opening 65 will act against Vane 61 in the same clockwise direction, the fluid in both instances leaving the crescent-shaped chambers through the slots 68 and 69 and passing through chamber 70 to the hydraulic motor 31. There is thus formed a positive displacement type motor the number of revolutions of which per unit time is a direct function of the volumeof fluid passing through the motor. This relationship is utilized, as will be hereinafter explained in detail, to operate a valve the movement of which towards its seat is directly related to the turning of the rotor 54.

'To secure the greatest efliciency of the vaned motor 46 it is essential that the contact between the vanes 61 and the inner surface of stationary ring 45 be substantially line contact at all times To, this end the outer surface of each vane is chamfered as at 72 in opposite directions resulting in the desired line contact at the apex or tip of the vane. I

It may be observed that chamfer 72 is exposed to fluid under pressure and consequently a radially inwardly directed component of force will be exerted upon vanes 61 by the fluid, tending to urge them away from the inner surface of ring 45. Such inward movement would, of course, result in leakage of thefluid past the vanes and would destroy the direct relationship between the revolutions of rotor 54 and the volume of fluid passing through the motor 46. To counteract the radial inward force of the fluid in

chambers

58 and 59, each

side plate

48, 49 is provided with a small axial opening 77 and 78, respectivelyythrough which fluid under pressure may be conducted from chamber 66- or chamber 70 into

annular recesses

73 and 74 formed in' rotor 54

adjacent end plates

48 and 49 respectively, said recesses being in communication with theends of slots 60 andthe inner surfaces of the vanes 61; f

The admission of fluid under pressure into slots 60 would introduce a leakage through rotor 54 from chamber 66, along slots 60, to chamber 70, and to avoid such leakage, pressure responsive valves (i. e. check valves) in the, form "of axially movable washers 75 and 76 are utilized. 'These washers are disposed in the chambers 73 and '74, respectively, and are acted upon by the fluid in such manner thatfluid tending to pass through the rotor from chamber66and into chamber 70 will act upon washer '76 to push it away from opening 78, and upon washer 75 to hold it against plate 48, thereby admitting fluid into recess '74 while covering opening 77 and effecting a seal between plate 48 and annular recess 73.

The'shut olf valve of the fuse is comprised of a conical seat 79 formed in housing part 38, and amovable valve member 80 having a frusto-conical nose portion 81 which is adapted to contact seat 79- and effectively close chamber 70 with respect to the outlet opening71. The manner in which valvebody 80 is moved toward seat 79 by motor 46 will now be described.

Valve body 80is hollow and has formed on the interior thereof a thread 82 (Figs. 7 and 8). "A screw 83 is adapted to cooperatew-ith threads 82 when there is differential rotation between valve body 80 and said screw 83. Valve body 80 is constrained to rotate with sleeve 53 by a pin84 passing through valve body 80 and extending into a slot 85 disposed-longitudinally of the exterior surface of the left-hand, and enlarged, end of sleeve 53.

Screw 83 has ratchet teeth 86 formed in the sidethcreof which cooperate with similar ratchet'teeth 87 formed on theend of a second sleeve 88 axially slidable on a central shaft 89. Sleeve 88 isconstrained to rotate with 6 shaft 89 'by a pin 90 operating in an axially disposed slot 91 in shaft 89. Obviously, the pin and slot may be reversed so that the pin is fixed to shaft 89 and the slot is formed in sleeve 88. A spring 92, compressed between an abutment 93 on the left-hand end (Figs. 7 and 8) of shaft 89 and screw 83 continuously urges the screw against sleeve 88. The thrust of the spring is taken by a shoulder 94 formed on sleeve 88 and abutting the left-hand end of sleeve 53.

It may be observed that if shaft 89 rotates at a different speed from the speed of sleeve 53, relative rotation will be set up between screw 83 and valve body 80 which will cause valve body 80 to move either to the left or to the right, depending upon the direction of relative rotation between the sleeve and shaft.

The means for producing relative rotation between sleeve 53 and shaft 89 is shown in Figs. 4, 5 and 6 and comprises a reducing gear mechanism disposed in chamber 66. Said reducing gear mechanism includes a drive gear 95 driven by, or formed integrally with, sleeve 53, which gear meshes with an intermediate gear 96 mounted on a counter-shaft 97 and adapted to drive another gear 98 mounted on shaft 97, through a ratchet mechanism 99. Gear 98 in turn meshes with a driven gear 100 pinned to shaft 89.

Gears

95 and 100 may have the same number of teeth, but gears 96 and 98 have'a different number of teeth, the difference being selected to provide the desired speed differential between the shaft 89 and sleeve 53. In the present instance, the difference is preferably one tooth.

Thus, gear 98 may have one tooth less than gear 96 so that the overall result is to cause gear 100 to rotate more slowly than gear 95 and hence a differential in speed between sleeve 53 and its associated valve 80, and shaft 89 and its associated nut 83 is established whereby axial movement of the valve may be had. In one typical example, gears 95 and 100 may have 18 teeth each, gear 96 may have 28 teeth and gear 98 may have 27 teeth, thereby establishing a ratio of .964 turns of the inner shaft 89 for each turn of the sleeve 53. For

each 28 turns of the outer shaft there will thus be an advance of the valve body 80 in an axial direction relative to sleeve 53 of one thread on screw 83. This ad- Vance, in the arrangement of parts herein illustrated, will be in thedirection of valve seat 79 so that ultimately valve body 80 will contact seat 79 and will stop the flow of fluid through the fuse.

If valve body 80 were to advance under the influence of screw 83 the entire distance required to effect a complete closing of the valve, that is, when. nose 81 is tightly seated against seat 79, there would be no way of effecting a reverse flow through the fuse as would be necessary to reset the fuse and to relieve pressure on the exhaust side of fluid motor 31. This condition, how ever, has been avoided in the present design in the manner now to be described. k

Referring to Fig. 7, it will be noted that as nose 81 approaches seat 79, a gradual constriction in the flow is produced, thereby creating a venturi eifect which causes the nose 81 to be drawn toward seat 79. This venturi effect is made use of by allowing screw 83 to move against the action of spring 92 to give a. quick cut-off of the fluid tending to flow through the fuse past seat 79. When the fluid is cut off, an immediate cessation of rotation of motor 46 ensues and valve 80 is thereafter held against its seat 79 by fluid under pressure acting against the righthand side (Figs. 7 and 8) of the valve.

,It may be noted that axial movement of valve 80 also resulted in axial movement of screw 83, sleeve 88 and pin 90 relative to shaft 89, thus separating shoulder 94 from the adjacent end of sleeve 53. This separation represents the amount of lost motion between valve body 80 and sleeve 53 or shaft 89 available when fluid pressure in the fuse is reversed, that is, when fluid under pressure is present in the left-hand threaded opening 71 and the right-hand opening 67 is vented. Reversal of fluid pressure on valve body 80 causes it to move to the right as viewed in Fig. 8 and take up the lost motion, thereby unseating the valve body and allowing fluid to flow through the fuse in a reverse direction.

The axial movement of screw 83 to the left relative to shaft 89 as viewed in Fig. 7 might under certain circumstances be brought about by the venturi effect at a time when spring 92 would be fully compressed but an opening would still be available between seat 79 and nose 81. If under these conditions the drive from shaft 89 and sleeve 88 were broken by a separation of the driving and driven portions of ratchet 87, the opening would permit fluid to continue to flow despite the fact that shaft 89 continued to rotate. No relative rotation between screw 83 and valve 80 would take place while the drive between shaft 89 and screw 83 remained broken and consequently the valve would remain in semi-opened condition as long as fluid flowed through it, i. e., until the entire system was drained which, of course, is precisely the condition which the fuse is expected to eliminate.

The effect just described is avoided in the present design by the pin and slot connection 90-91 between sleeve 88 and shaft 89 and by the use of a spring 101 which continuously urges sleeve 88 against screw 83, but is weaker than spring 92 so as not to interfere materially with the operation of the latter. Thus, when valve body 80 is drawn to the left as viewed in Fig.7 by the venturi action and draws with it screw 83, the axial movement of screw 83 on shaft 89 is followed by sleeve 88, and the drive of the screw 83 is therefore uninterrupted by this axial movement. The drive thus continues until the valve is seated and flow of fluid ceases.

The fuse described herein is reset automatically upon a reversal of flow of fluid therethrough. It is desirable that the fuse be reset in the shortest possible time and that the fuse shall not limit the quantity of fluid flowing reversely through it.

The first condition, namely, that the fuse be reset as quickly as possible, is met by greatly increasing the relative rotation between screw 83 and valve body 80 during reverse flow of fluid through the fuse. This greatly increased relative rotation is brought about by holding shaft 89 against rotation while at the same time directly driving valve body 89 with sleeve 53 and rotor 54. During such reverse flow, motor 46 rotates in a counterclockwise direction as viewed in Fig. 9, the fluid under pressure entering the motor 46 through openings 68, 69 and leaving through openings 65, 64. Consequently, sleeve 53 likewise rotates in a counterclockwise direction. The means by which shaft 89 is held against rotation comprises a one-way brake interposed between gear 98 and countershaft 97. This brake is shown to better advantage in Fig. and is comprised of a plurality of rollers 102 disposed in cam slots 103 formed in the outer periphery of an enlarged portion 104 of counter-shaft 97. It is understood that counter-shaft 97 is held against rotation by any suitable means such as a press fit into housing portion 37 and plate 49.

With gear 98 held against rotation and gear 96 constantly in mesh with rotating gear 95 which, as stated above, is constrained to rotate at all times with sleeve 53, the drive between

gears

96 and 98 is broken by the release of ratchet 99. As the teeth of ratchet 99 move over one another, gear 96 s reciprocated on countershaft 97 against a spring 105 compressed between plate 49 and the side of gear 96. Since gear 98 is held against rotation in a reverse direction, sleeve 88 is likewise held against rotation and screw 83, through its ratchet connection with sleeve 88, is likewise held against rotation. The rotating sleeve 53, however, causes the directly connected valve body 80 to rotate at the same speed, thereby moving valve 80 axially to the right as viewed in Fig. 7, away from seat 79 at the rate of one thread per revolution.- This -movement of valve to the right continues until a radially inwardly extending pin 106 on valve 80 strikes an axially extending pin 107 on screw 83. When this occurs, both screw 83 and valve 80 rotate as a unit, that is, relative rotation between these two members ceases and hence axial movement of valve 80 on sleeve 53 likewise ceases, despite continued flow of fluid in a reverse direction through the fuse and the continued resultant rotation of cylinder 54.

The cessation of relative rotation between screw 83 and valve 88 is made possible by the release of the drive between. sleeve 88 and screw 83 by

ratchet teeth

86 and 87, these teeth riding over one another and causing the valve and screw 83 to reciprocate slightly relative to shaft 89 and sleeve 53 under the action of spring 92.

After valve 80 has moved to the right as far as it is possible for it to go, the fuse is reset and'is in readiness to function again when flow through the fuse is reversed.

It may be observed that among the features of this invention is the use of two inlet and outlet passages to fluid motor 46, together with diametrically

opposed chambers

58 and 59, which results in a balanced design of motor 46 and in concentric shafting, rotor and housing. Such concentric design simplifies the manufacture of the fuse.

Due to the fact that shaft 89 is held stationary during the re-setting cycle, and that gears 95, 96, 98 and 108 have numbers of teeth equal to, or proportionate to, the numbers given above as an example, the fuse will reset after but the quantity of fluid has passed in the reverse direction as was required to cause the fuse to shut off the line. 7

Because of the large size of the

openings

64, 65, 68 and 69 through which the fluid flows, the device is not sensitive to, nor affected by, microscopic particles of foreign matter that may be found even in the cleanest of fluids used in hydraulic systems. The low friction forces developed in the relatively rotating parts of the device render it insensitive to fluctuations in the flow rate and to variations in the pressure of the fluid passing through it. Furthermore, the device will operate as well under low unit pressures as it will under high unit pressures, within the limits of the strength of the

housing parts

37, 38. g r

Since each of themoving parts of the fuseis positively related to every other moving part, the fuse of this invention will notbe affected by the normal forces of acceleration, vibration and shock that are encountered in aircraft type hydraulic systems, for example, or in other systems used with vehicles or other moving equipment. It is also relatively insensible to variations in viscosity, density or temperature of fluids normally used in hydraulic systems.

Due to the positive displacement characteristic of the fluid motor 46, the device has been found to be accurate to within 5% of its rated capacity. This means'that the total quantity of fluid in the system may be reduced to slightly more than 5% over the maximum required to operate the fluid motors in the system, instead of the over the maximum required in priordesigns. The saving in weight of both the reservoir and the fluid is one of the more beneficial results of the herein described fuse.

It is understood that the foregoing description is merely illustrative of a preferred embodiment of the invention and that the scope of the invention therefore is not to be limited thereto but is to be determined by the appended claims.

We claim: 7 Y

1. A device for automatically stopping the flow of fluid under pressure in a line, said device comprising a positive displacement pressure differential operated motor rotated by the fluid under pressure in the line, a valve adapted to stop the flow of fluid in the line, said valve including a stationary seat and a movable valve body I 9 adapted to contact theseat, means connecting the motor and movable valve body'and adapted to move the valve body in timed relation to the rotation of the motor, said connecting means including a lost motion connection whereby the valve body may move'independently of the connecting means in response to fluid pressure acting upon theval vebody, said connecting means being adapted to move the valve body to aposition in proximity to the valve seat and said valve body being moved through said lost motion connection to contact the valve seat by the fluid under pressure in the line.

2. A device for automatically stopping the flow of fluid under pressure in a line, said device comprising a rotatable positive displacement fluid motorin the line and operated by the fluidflowing'in the line, a shut off valve in the: line, screw means foropening and closing the valve, speed reducing means adapted to drive the screw means from the motor, and a lost motion connection between the screw means and the motor, said valve being brought toa partially closed position by the speed reducing means, and being completely closed by the pressure of the fluid acting upon the valve and moving the valve independently I of the speed reducing means through the lost motion connection, I y

3. A device as described in' claim 2, said speed reducing means comprisingca drive shaft driven by the fluid motor, a, driven shaft adapted-to be connected to the screw means, gearing adaptedto transmit a drive from the drive a driven shaft adapted to be connected to the screw means through the lost motion connection, a gear driven by the drive shaft, a gear on the driven shaftand rotatable in timed relation therewith, reduction gearing connecting the ,driving and driven shaft ,gearssaid valve including a fixedseat and a valve body movable toward and away.

from theseat, means .forrotating the valve body in timed relation with the drive shaft, and threads on the valve body engaged by the screw means whereby the valve body aye; brought to a partially. closed position as aforesaid. J ,SLTA deVice forautomatically stopping the how of fluid underpressure in a .line after ,a predetermined volume of fluid has passed throughtheline, said device comprising [a fixed circular valveseat,,a rotatable valve body movable toward the seat to close the .line, an axially fixed drive shaft for the ;valve body, an axially slidablepdriving connection 'betweenqthe drive shaft and the valve body, a normally axially fixed screw, threads on thevalve body engag'eable by the screw, and means for establishing relative rotation between the screw and .valve body to cause said valve body 7 to move axially toward or away from the seat to close or open said valve,

said'last-mentionejd means including a fluid motor rotatable in accordance with the volume of fluid passing "fluidhas passed through the line, 'said device comprising a fixed circular valve seat, a rotatable valve body movable axially toward the seat, to close the line, an axially fixed drive shaft 'for the valve body, an axially slidable driving connection bet-ween the drive 'shaft and valve body, a mormally axially fixed screw, threads on the valve body engage-able by the screw, means for establishing relative rotation between the screw and. valve body to cause said valve tbodyto move axially toward zoraway from the seat to close or open said valve, and resilient axially yieldable means for holding the screw in a normally axially fixed position, said valve body and seat forming a venturi ,as the valve body approaches the seat and rel0 sulting in an increase in pressure on the valve body in a valve closing direction which overcomes the 'yieldable means and causes the screw to move with the valve axially relative to the drive shaft.

7. A device as described in claim 6, said means for valve body including a rotatable fluid pressure differential motor'operated by the fluid passing through the line, and speed reducing means connected between the drive shaft and screw.

9. A fluid motor comprising a shaft, a cylindrical rotor mounted on the shaft for rotation therewith, said rotor having radially inwardly extending axially disposed slots, a recess on each side of the rotor, each recess being in communication with each of the slots, radially slidable vanes in the slots, a relatively fixed ring encircling the rotor and having its inner surface contoured to form crescent-shaped chambers with the rotor, resilient means for urging the vanes against the contoured inner surface,

side sealing plates on either side of the rotor, said plates having passageways therethrough communicating with the recesses and having inlet and outlet passages communicating with the crescent-shaped chambers, and check valves in the openings and adapted to open the passageway in one plate while closing the passageway in the other plate, whereby to prevent axial flow of fluid through the slots.

10. A fluid motor as described in claim 9, the outer ends of the vanes being chamfered such that a radial inward component of force is exerted upon the vanes by the fluid under pressure in the crescent-shaped chambers,

said fluid under pressure also entering the slots through one of said openings in the side plates to produce a balancing radial outward force on the vanes.

, 11. A fluid motor as" described in claim 9 at least one of said check valves comprising an axially movable washer disposed in one of 'said ecesses and adapted to cover the passageway through the plate adjacent said recess in response'to fluid pressure.-

12. A device for automatically stopping the flow of fluid under pressure in a line, said device comprising a rotatable positive displacement fluidmotor in the line and operated by the fluid flowing in the line, said motor comprising a shaft, a cylindrical rotor mounted on the shaft for rotation therewith, said rotor having radially inwardly extending axially disposed slots, the rotor having .a .recess on each side thereof, each recess being in communication with each of the slots, radially slidable vanes in the slots,-a relatively fixed ring encircling the rotor and having its inner surface contoured to form a crescentshaped chamber with the rotor, resilient means for urging the vanes against the said contoured inner surface of the ring, side sealing plates on either side of the rotor, said plates having passageways therethrough communicating with the recesses and with the fluid in the line, and fluid pressure operated check valves in the recesses and adapted t to open the passageway in one plate while closing the beingbrought to a partially closedposition by the speed reducing means, and being completely closed by the pres sure of the fluid acting upon the valve and moving the valve independently of the speed reducing means through the lost motion connection.

13. A device for automatically stopping theflow of fluid under pressure in a line after a predetermined vol- 11 urne of fluid has passed through the line, said device comprising a fixed circular valve seat, a rotatable valve body movable axially toward the seat to close the line,

an axially fixed drive shaft for the valve body, an axially slidable driving connection between the drive shaft and valve body, a second shaft concentric with the first shaft, a screw mounted for free rotation on said second shaft, threads on the valve body engageable by the screw, a sleeve on the second shaft, an axial lost motion connection between the sleeve and second shaft, an axially engagcable torque release drive mechanism between the sleeve and screw, resilient means urging the screw and sleeve together and away from the valve seat to engage the torque release mechanism, means for establishing relative rotation between the shafts whereby to establish relative rotation between the screw and valve body to cause said valve body to move axially toward or away from the seat to close or open said valve, said valve body and seat forming a venturi as'the valve body approaches the seat and resulting in an increase in pressure on the valve body in a closing direction which overcomes the resilient means and causes the screw to move with the valve axially relative to the second shaft, and means on the screw and valve interengageable with one another to prevent relative rotation therebetween when the valve is moved in a valve opening direction to the limit of its movement in such direction, the torque release connection between the screw and sleeve breaking the drive therebetween when relative rotation between the valve body and screw is prevented as aforesaid.

14. A device for automatically stopping the flow of fluid under pressure in a line, said device comprising a rotatable positive displacement fluid motor in the line and operated by the fluid flowing in the line, a shut-01f valve in the line, screw means for opening and closing the valve, reversible speed reducing means adapted to drive the screw means from the motor, said speed reducing means including means for establishing a higher speed 7 reduction in a valve closing direction of rotation thereof than in a valve opening direction, and an axial lost motion connection between the screw means and the motor, said valve being brought to a partially closed position by the speed reducing means, and being completely closed by the pressure of the fluid acting upon the valve and moving the valve independently of the speed reducing means through the lost motion connection. I

15. A device in accordance with claim 14, said speed reducing means comprising a drive shaft driven by the with the gear on the drive shaft, a second gear on the countershaft inmesh with the gear on thedriven shaft, torq-ue releasable driving means between the counters shaft gears to transmit a drive from one said countershaft gear to the other, and one-way brake means adapted to prevent rotation of the driven shaft in reverse direction, the numbers of teeth on the gears in the speed reducing means being such that the speed of the driven shaft is slower than the speed of the drive shaft in a forward direction, whereby when the flow of fluid in the line is reversed through the device and the motor. is driven by the fluid in a reverse direction, the driven shaft is held against rotation-and. the valve is moved to'its open position at a greater speed than the speed at which being in communication with each of the slots and with the fluid in the line, radially slidable vanes in the slots, a relatively fixed ring encircling the rotor and having its inner surface contoured to form crescent-shaped chambers with the cylindrical surface of the rotor, resilient means for urging the vanes against the contoured inner surface, side sealing plates on either side of the rotor, said plates having passageways therethrough communieating with the recessesto introduce fluid under pressure to the inner ends of the vanes, and checkvalves in the openings and adapted to open the passageway in one plate while closing the passageway in the other plate, whereby to prevent axial flow of fluid through the slots; a shut-off valve in the line comprising a fixed seat and a valve body movable toward and away from the seat to close and open the line to the'device, threaded means on the valve body, a screw engageable with the threaded means and rotatable relatively thereto to cause the valve body to move toward or away from the seat, and means for establishing relative rotation between the screw means and valve body, said relative rotation establishing means comprising a sleeve driven by the fluid motor, said shaft being disposed within thesleeve and rotatable relative thereto, means for driving the valve body with the sleeve but permitting relative axial movement therebetween, means for driving the screw means from the shaft, and speed reducing means connecting the sleeve and shaft, said speed reducing means comprising'a gear on the sleeve and rotatable therewith, a gear on the shaft and rotatable therewith, a fixed countershaft, a gear on the countershaft meshing with the-gear on the sleeve, a second gear on the countershaft meshing with the gear on the shaft, torque releasable drive means between the countershaft gears and effective to drive the driven shaft ina forward direction, and one-way brake means for holding the second countershaft gear against "rotation in a reversed direction, the means for driving the screw from the driven shaft including a lost motion connection operable in an axial direction, said valve being brought to a partially closed position by the speed reducing means, and being completely closed by the pressure of the fluid acting upon the valve and moving the valve independently of the speed reducing means through the lost motion connection.

17. A device as described in claim 16, said' means for driving a screw means from the driven shaft'in'cluding further a torque releasable connection whereby the screw means may be driven independently of the driven shaft, and interengageable means between the valve body and the screw means and operable when the valve is in fully open position to prevent further relative rotation between the valvebody and screw means, they releasable connection at such time being effective to break the connection between the screw means and d1ivc'n shaft.

ReferencesCitedint he file of this patent UNITED STATES PATENTS